The United States already imports more oil from Canada than anywhere else. But with oil prices on the rise, the controversial oil sands are likely to become even more economically viable, despite experts' warnings about environmental risks.

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Of Canada's 175 billion barrels of oil that can be recovered, 170 billion barrels come from the oil sands in the Alberta region.

The oil sands cover 54,826 square miles, an area bigger than England and almost the size of Florida.

It takes about two tons of mined oil sands to produce one barrel of crude oil. One operating mine in Alberta has excavated more soil than the Great Pyramid of Cheops, the Great Wall of China, the Suez Canal and the world’s 10 biggest dams combined.

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Oil sands operations divert 349 million cubic meters of water per year from the local river — twice that used by the city of Calgary.